"Scottish independence would entail significant economic risk," the think tank said. It pointed out estimates from the Institute for Fiscal Studies (IFS) which suggest an independent Scotland would have a budget deficit of 9.4 per cent of GDP this year, compared to 2.9 per cent for the entire UK.

The IFS calculations, made before the referendum and thus before George Osborne ditched his budget surplus target, also forecast a deficit of 6.2 per cent by the end of the decade, while the entire UK was on course to have balanced the books.

The CPS acknowledged, however, that "Nicola Sturgeon’s push for independence does have some logic from a democratic standpoint. Scotland is being taken out of the EU despite voting to remain within the institution.

"There is a precedent for a small, romantic country, surrounded by hundreds of islands, perched on the extremity of Europe, seeking membership of the Euro: Greece."

The CPS added: "Of course, it would be impertinent to suggest that Scotland’s circumstances are directly equivalent to those of Greece, but it does undoubtedly serve as a useful reminder that countries with challenging public finances can end up suffering inside the euro."

A spokesperson for the SNP said: "The reality is that Scotland is the wealthiest part of the UK per head outside London and south east England.

"The biggest risk to Scotland’s economic stability and security – without any question – is the threat to take us out of the EU and a single market of almost 500 million people."